Fire extinguishing process



FIRE EXTINGUISI-HNG PROCESS Luis E. Eckelmann, Brooklyn, and George E.Ferguson,

Spring Valley, N. Y., assignors to Pyrene Manufacturing Company, Newark,N. J., a corporation of Delaware No Drawing. Application February 20,1953, 'Serial No. 338,132

3 Claims. (Cl. 169'1) The present invention relates to a novel processfor extinguishing dual fires involving both metals and organicchemicals, particularly organic liquid hydrocarbons.

It is an object of the present invention to provide a novel process forextinguishing dual or combined fires of combustible metals with those ofinflammable organic chemicals in which the metal may be immersed or incontact with, which process is eflicient, dependable and spectacular inits results, and which uses materials which may be easily stored andwhich produce no toxic byproducts.

It is a further object of the invention to provide a simple process forextinguishihng dual metal and solvent fires which requires a minimum ofequipment and only inexpensive materials.

Other objects will be apparent to those skilled in the art after readingthe specification which follows.

Fires caused by the combustion of metals, and particularly the lightmetals, have presented a problem in recent years due to greatlyincreased production of the light metals and their wide-spreadcommercial application. These light metals, which include sodium,lithium, potassium, magnesium and aluminum, burn with an intense, hotflame when ignited. Also, some of the heavier metals, such as iron andzinc, are prone to ignite and burn at a very high temperature. Most ofthe common fireextinguishing materials are not satisfactory for treatingthe fires of the combustible metals, for most react violently with thehot, burning metal and only serve to spread the fire. Special methodsand materials had to be designed to combat these fires.

A fire extinguishing problem which has to the present time defied asatisfactory solution, and which has become a problem of increasingimportance to those charged with safety and fire extinguishing, is thatinvolving a dual or combined fire of a metal and an inflammable organicchemical. It is believed apparent to those skilled in the art that thepresence of the burning organic chemical greatly complicates andaggravates the problem of extinguishing the metal fire as well aspresenting the problem of extinguishing the burning chemical.

It is a common practice to store turnings, filings, dust, as well asbars and other physical forms of metals, and particularly light metals,suspended or immersed in an organic chemical liquid. For example,powdered leaf aluminum is being used in ever increasing amounts as apigment in aluminum paints. Aluminum powder, in its finely dividedstate, will dust into the air very readily and can ignite spontaneouslyin the air. It can also ignite spontaneously after being moistened withwater. To overcome these fire dangers, and to aid in readilyincorporating the aluminum powder into a paint vehicle, it is commonpractice to store the powder suspended in a liquid hydrocarbon organicmaterial. The hydrocarbon liquid used in making this aluminum paste maybe ligroin or V. M. P. naphtha (petroleum fractions having a boilingpoint between that of gasoline and kerosene), although other petroleumfractions may be used which nited tates Patent O ice are compatible withthe other paint ingredients. The amount of hydrocarbon used may besuitably varied, but it has been found convenient to use an amount ofabout 10% of the weight of the total aluminum paste. Others of the lightmetals are often immersed in hydrocarbon liquids to prevent undueoxidation or other undesirable reactions from taking place. Thus sodiumand potassium are frequently stored in an oil or hydrocarbon immersion.

While the storing of the combustible metals as an immersion in anorganic liquid alleviates somewhat the incidence of fires of thecombustible metals, it creates a fire hazard all of its own. The presentinvention provides a process for extinguishing dual fires of thesecompositions.

Our invention comprises a novel process for extinguishing dual fires ofa combustible metal and an inflammable organic liquid, which comprisesplacing a liquid film of an aromatic ester of a phosphoric acid over theburning liquid and metal. The process is particularly applicable to dualfires of the powdered light metals, such as aluminum and magnesium,immersed in a liquid petroleum hydrocarbon, such as ligroin and naphtha.The process finds ready application in dual fires of combustible metalsin any state of physical division, such as turnings, dust, powder, bars,etc., and including sodium, potassium, zinc, iron, lithium and zirconiumin conjunction with organic liquids, particularly the petroleumhydrocarbons.

,A single aromatic ester of a phosphorus acid may be used alone or in amixture of various aromatic esters of a phosphorus acid. Among theesters contemplated for use in our process are the aromatic tri-estersof phosphoric acid, particularly such as tri-aryl phosphates asdiphenyl-mono-(ortho-xenyl) phosphate, tri-(para-tertiarybutylphenyl)phosphate, di-(para-tertiary-butylphenyl)- mono phenyl phosphate and (4tertiary butylphenyl) (phenyl) (ortho-xenyl) phosphate, or the aromatictriesters of phosphorus acid, such as di-(2-xenyl) phenyl phosphite, andsuch esters of thiophosphoric acid as phenyl di-(meta-tolyl)thiophosphate and diphenyl orthoxenyl thiophosphate. It is essential tosuccessful application of the process that the ester used be a liquid atthe temperatures at which they will be stored in readiness for instantusage for extinguishing fires.

Of the aromatic esters of a phosphorus acid which have been tested todate, those of the tri-aryl phosphates have given best results.Diphenyl-mono-(ortho-xenyl) phosphate in particular has givenspectacular results and appears to be ideally suited for use in ourprocess in all respects. So satisfactory has the use of this ester beenthat we wish to particularly direct our process to the use of thisester.

In the application of our process to dual fires it is our purpose toprovide a layer or film of the viscous liquid phosphorus acid aromaticesters over the surface of the burning composition. Best results are notobtained by spraying, sprinkling or squirting the ester over the surfaceof the burning composition. It is important not to break the surface ofthe burning liquid and this may easily happen if the ester is sprayed,sprinkled or squirted on. It is preferred that the masking of theburning liquid with the ester be eifected by flowing the ester over theburning surface. Preferably the ester, which is a highly viscous liquid,is flowed out onto the surface of the burning composition much likesyrup is poured over the surface of a pancake. This technique ofapplication is a significant feature of our process and constitutes animportant phase of our invention. One means for flowing the ester overthe surface of the burning composition is to slowly pour the ester in athin stream from a supply chamber over the side of the container holdingthe burning composition and onto the contents.

available.

The storage vessel holding the ester should preferably be equipped witha delivery channel having a flow -regulating means.

By practicing our process, dual fires of a burning metal and an organicliquid are easily -and quickly 'extin guished with no flashbacks,reaction or sputtering as the aromatic ester of the phosphorus acid isapplied. Also,

no undesirable or even noticeable fumes are produced- I ess of theinvention will hereinafter be described. This is done solely by way ofexample and is intended neither to delineate the scope of the inventionnor limit the ambit of the appended claims.

In a test demonstration, an open steel tank 4 ft-x 8 ft. x 4 in. wasfilled with about 100 lbs. of a powdered aluminum paste containing about10% by weight of naphtha. Over one end of 'the tank was installed a twoinch pipe leading to a drum of diphenyl-rnono-(orthoxenyl) phosphate.The pipe was equipped with a quiclo opening knife valve. ignited andpermitted to burn for 1-0 minutes, during which time the metal hadbecome involved in several very hot fires. The extinguishing fluid wasslowly released and permitted to flow gently until it covered theburning surface. Within about 2 or 3 minutes all of the fires had beencompletely extinguished without any sputtering or evolution of anyundesirable or noticeable fumes. These test conditions are believed toparallel field conditions and present the severest test conditions Theresults show that the process provides a The powdered aluminum paste wassatisfactory solution to the problem presented by dual metal andhydrocarbon fires.

The terms and expressions which we have employed are used as terms ofdescription and not of limitation, and we have no intention, in the useof such terms and expressions, of excluding any equivalents ofthefeatures shown and described or portions thereof, but recognize thatvarious modifications are possible within the scope of the inventionclaimed.

What is claimed is:

l. A process for extinguishing dual fires of a finely dividedcombustible light metal and aliquid petroleum hydrocarbon whichcomprises pouring a layer of an aromatic tri-ester of phosphoric acidover the surface of the burning composition with the use of only suchforce as will spread the phosphoric acid ester over the surface of theburning composition without substantially penetrating the surface.

2. A process for extinguishing dual fires of a finely divided lightmetal selected from the class consisting of aluminum and magnesium and aliquid petroleum hydrocarbon which comprises pouring a layer ofdiphenylmono-(ortho-xenyl) phosphate over the surface of the burningcomposition with the use of only such force as will spread saidphosphate over the surface of the burning composition withoutsubstantially penetrating the phate over the surface of the burningaluminum :paste without substantially penetrating its surface.

References Cited in the file of this patent UNITED STATES PATENTS2,307,083 Thrune Jan. 5, 1943

1. A PROCESS FOR EXTINGUISHING DUAL FIRES OF A FINELY DIVIDEDCOMBUSTIBLE LIGHT METAL AND A LIGHT PETROLEUM HYDROCARBON WHICHCOMPRISES POURING A LAYER OF AN AROMATIC TRI-ESTER OF PHOSPHORIC ACIDOVER THE SURFACE OF THE BURNING COMPOSITION WITH THE USE OF ONLY SUCHFORCE AS WILL SPREAD THE PHOSPHORIC ACID ESTER OVER THE SURFACE OF THEBURNING COMPOSITION WITHOUT SUBSTANTIALLY PENETRATING THE SURFACE.